Preparation method and application of anti-icing, self-cleaning and radiant cooling multifunctional coating

Abstract

The present invention discloses a multifunctional coating with anti-icing, radiant cooling, and self-cleaning properties, and its preparation method. The coating's main components include SiO2 nanoparticles, TiO2 nanoparticles, α-phosphogypsum, epoxy resin (E51), polyethyleneimine (PEI), polydimethylsiloxane (PDMS), and its curing agent. A simple blending method is used to prepare the slurry, followed by a doctor blade coating process. This multifunctional coating exhibits anti-icing, radiant cooling, and self-cleaning properties. The coating is prepared without the use of fluorine-containing reagents, making it environmentally friendly. Its self-cleaning properties protect the surface from external contamination, thereby maintaining stable anti-icing and radiant cooling performance. Furthermore, the composite coating demonstrated excellent durability in mechanical wear tests, chemical stability tests, and outdoor weathering tests.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional coatings, and in particular relates to an anti-icing, self-cleaning, and radiation cooling multifunctional coating and a preparation method thereof. Background Art

[0002] As rapidly increasing energy consumption has raised concerns about energy depletion and severe environmental impacts, the development of inexpensive and efficient cooling coatings and refrigeration technologies that can mitigate global energy demand and climate change is of great importance. Radiative cooling (RC) is a novel, energy-free method for saving energy and lowering ambient temperature. It strongly reflects sunlight in the visible and near-infrared wavelengths (0.3-2.5 μm) and transmits infrared heat to the universe through the atmospheric window (8-13 μm). Cooling coatings are often applied to outdoor surfaces such as electrical equipment and rooftops. Long-term exposure to the elements, such as rain, dust accumulation, and sunlight, can degrade the material's optical properties, reducing its reflectivity and thus its cooling effectiveness. In particular, in extreme winter conditions, ice accumulation and melting can severely damage the coating's microstructure, dramatically diminishing its radiative cooling effect. Therefore, developing coatings that simultaneously possess superhydrophobic, anti-icing, and radiative cooling properties is crucial for the outdoor durability of radiative cooling coatings. However, reports on such multifunctional composites are limited. Existing superhydrophobic materials are mainly achieved by constructing micro-nano double rough structures with low surface energy. The most common method is to use SiO2 as the main particle to construct a superhydrophobic surface. The radiative cooling coating requires a material with high reflectivity and high emissivity to form a mesh structure to achieve the best radiative cooling effect.

[0003] Although adding radiative cooling materials with high emissivity or high reflectivity, such as TiO2, ZnO, MgTiO3, SrTiO3, and BaTiO3, to super-hydrophobic coatings can improve the cooling performance of the coating to a certain extent, the effect is still not ideal, mainly because it is difficult for such materials to have both high emissivity and high reflectivity. At the same time, these material additives usually lead to a decrease in hydrophobicity. Summary of the Invention

[0004] In order to solve the technical difficulties of existing super-hydrophobic radiant cooling coatings, the present invention proposes a super-hydrophobic, anti-icing and radiant cooling multifunctional coating based on E51-PEI-PDMS-SiO2-TiO2-α-phosphogypsum and its preparation method, an anti-icing, self-cleaning, radiant cooling multifunctional coating and its preparation method, which solves the problem that existing coatings are difficult to take into account anti-icing, cooling, self-cleaning and excellent outdoor durability.

[0005] The technical solution of the present invention:

[0006] TiO2 was modified using NaOH, Na2SO4, KH570 and α-phosphogypsum to improve its hydrophobicity and reflectivity. Superhydrophobic SiO2 nanoparticles, TiO2 nanoparticles and modified α-phosphogypsum were then used as the main fillers. Epoxy resin (E51) and polyethyleneimine (PEI) were added. PEI has highly reactive primary and secondary amines, which can easily react with the epoxy groups in E51 to form a stable cross-linked network, thereby improving the connection strength within the coating and between the coating and the substrate. Finally, polydimethylsiloxane (PDMS) and its curing agent were added to cross-link and cure the coating after the solvent evaporated, further improving its mechanical properties.

[0007] An anti-icing, self-cleaning, radiative cooling multifunctional coating and a preparation method thereof, comprising the following steps:

[0008] Step 1: Add α-phosphogypsum, NaOH and Na2SO4 to deionized water, stir, add TiO2 nanoparticles, continue stirring, filter, microwave, wash and dry to obtain α-phosphogypsum-TiO2 mixed powder;

[0009] Step 2: Anhydrous ethanol, deionized water and KH570 are mixed and stirred, and after heating, the mixed powder obtained in step 1 is added, and the mixture is further stirred under heating and regulated, and then filtered, washed, dried, ground and sieved to obtain modified TiO2 nanoparticles;

[0010] Step 3: adding super-hydrophobic SiO2 nanoparticles and modified TiO2 nanoparticles into an ethyl acetate dispersion solvent, and obtaining a mixed suspension of SiO2 and modified TiO2 after ultrasonic dispersion;

[0011] Step 4: Add E51 and PEI to the mixed suspension obtained in step 3 and stir to obtain a mixed solution;

[0012] Step 5: Add PDMS and its curing agent to the mixed solution obtained in step 4 and stir to obtain a super hydrophobic coating;

[0013] Step 6: The coating obtained in step 5 is coated on the substrate by a doctor blade method, and after solvent drying, an anti-icing, radiation cooling, and self-cleaning multifunctional coating of SiO2, TiO2 and hydrophobically modified α-phosphogypsum is obtained.

[0014] In the step 1, the mass ratio of TiO2: α-phosphogypsum: NaOH: Na2SO4 is 0.3~3: 3~9: 1~5: 0.2~2; the microwave power is 60W~150W, and the microwave irradiation time is 2~8 minutes.

[0015] Furthermore, as a preferred embodiment, in step 1, the mass ratio of TiO2: α-phosphogypsum: NaOH: Na2SO4 is 1:6: 3: 0.5; the magnetic stirring speed is 800 r / min;

[0016] The microwave power was 100 W, and the microwave irradiation time was 3-5 min.

[0017] In step 2, the mass concentration of KH570 is 0.025-1 g / mL, and the mass ratio of KH570: modified TiO2 is 0.2~1: 2~12, preferably 0.53: 6; the stirring temperature is 50°C~80°C, preferably 60°C.

[0018] In step 3, the particle size of the super-hydrophobic SiO2 nanoparticles is 7-40 nm, and the specific surface area is 100-200 m 2 / g; the particle size of modified TiO2 is 90-120 mesh, the total mass concentration of the suspension of superhydrophobic SiO2 nanoparticles and modified TiO2 is 0.053-0.1 g / mL, and the mass ratio of superhydrophobic SiO2 nanoparticles: modified TiO2 is 1:0.1~3:2.

[0019] In step 4, the mass ratio of E51:PEI is 3-5:1, and the stirring temperature is 65-75°C.

[0020] In step 5, the PDMS mixture has a PDMS mass concentration of 0.013-0.1 g / mL, and after stirring for 30 min-1 h, the mixture is cured at 120-140 ° C for 2 to 3 h.

[0021] In step 6, the coating comprises, by weight, 30 to 50 parts of superhydrophobic SiO2 nanoparticles, 5 to 50 parts of modified TiO2 nanoparticles, 20-30 parts of E51, 10-15 parts of PEI, and 15-20 parts of PDMS, with the mass ratio of PDMS to curing agent being 10-20:1.

[0022] In a preferred embodiment, the coating comprises, by weight, 30 to 50 parts of super-hydrophobic SiO2 nanoparticles, 5 to 50 parts of modified TiO2 nanoparticles, 30 parts of E51, 10 parts of PEI, and 20 parts of PDMS, with the mass ratio of PDMS to curing agent being 10:1.

[0023] In step 6, the scraping film thickness of the doctor blade method is 100-300 μm (preferably 200 μm), and the material of the substrate includes any one of a glass sheet, an aluminum sheet, a copper sheet, and a carbon steel sheet.

[0024] The coating obtained by the preparation method of the anti-icing, radiant cooling and self-cleaning multifunctional coating is used in materials with any one or more properties of anti-icing, radiant cooling and self-cleaning.

[0025] Beneficial effects of the present invention:

[0026] 1. Multifunctionality: The multifunctional coating of the present invention has anti-icing, self-cleaning, and radiant cooling properties, as well as excellent mechanical stability, aging resistance, and acid and alkali resistance.

[0027] 2. Good durability. In outdoor application scenarios, the multifunctional coating samples were exposed for two months without any significant degradation in coating performance.

[0028] 3. The multifunctional coating of the present invention is difficult for hydrophilic pollutants to adhere to, and can be applied to various fields such as self-cleaning, anti-icing, deicing, and hydrophobicity.

[0029] 4. The multifunctional coating of the present invention does not contain toxic reagents and is environmentally friendly.

[0030] 5. The present invention uses α-phosphogypsum to modify TiO2. On the one hand, α-phosphogypsum particles and TiO2 nanoparticles are used to form a micro-nano double rough structure, and KH570 is used to modify the surface energy thereof to make it superhydrophobic. On the other hand, phosphogypsum and TiO2 nanoparticles are hybridized to significantly improve their reflectivity, thereby significantly improving the radiation cooling effect of the coating.

[0031] 6. The present invention utilizes epoxy resin E51 and polyethyleneimine PEI to cross-link with each other, playing a connecting role between the two nanoparticles and the substrate. The addition of PDMS makes the coating strong and durable, and gives the coating good mechanical stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Graphs showing the water droplet contact angle test results for the coatings in Examples 1, 2, 3, 4, 5, 6, and 7.

[0033] Figure 2 Graphs showing the water droplet rolling angle test results for the coatings in Examples 1, 2, 3, 4, 5, 6, and 7.

[0034] Figure 3 These are experimental diagrams of the coatings on the aluminum substrates of Examples 2, 3, 4, 5, and 6 in ice melting tests.

[0035] Figure 4 The graph shows the ice-shedding force test results of the coating on the aluminum substrate of Examples 2, 3, 4, 5, and 6 after freezing of different volumes of deionized water by external force.

[0036] Figure 5Graphs showing the test results of water droplet contact angle and rolling angle of the coating on the aluminum substrate of Examples 2, 3, 4, 5, and 6 after multiple freezing and thawing cycles.

[0037] Figure 6 This is a graph showing the radiation cooling test results of the coating in Example 1 under direct sunlight.

[0038] Figure 7 This is a temperature difference result diagram of the radiation cooling test of the coating in Example 1 under direct sunlight.

[0039] Figure 8 Graphs showing the radiation cooling test results of the coatings of Examples 2, 3, 4, 5, and 6 under direct sunlight.

[0040] Figure 9 This is a graph showing the temperature difference results of the radiation cooling test of the coatings of Examples 2, 3, 4, 5, and 6 under direct sunlight.

[0041] Figure 10 Graphs showing the test results of water drop contact angle and rolling angle of the coatings in Examples 2, 3, 4, 5, and 6 in a cyclic impact test with 20 g gravel at a height of 40 cm.

[0042] Figure 11 Graphs showing the test results of water drop contact angle and rolling angle of the coatings in Examples 2, 3, 4, 5, and 6 in a cyclic friction test on 1000-grit sandpaper with a load of 50 g.

[0043] Figure 12 Graphs showing the water drop contact angle and rolling angle test results of the coatings in Examples 2, 3, 4, 5, and 6 after being immersed in a pH = 2 HCl solution for 10 days.

[0044] Figure 13 Graphs showing the water drop contact angle and rolling angle test results of the coatings in Examples 2, 3, 4, 5, and 6 after being immersed in a NaOH solution with a pH of 10 for 10 days.

[0045] Figure 14 Graphs showing the test results of water drop contact angle and rolling angle of the coatings in Examples 2, 3, 4, 5, and 6 after being placed outdoors for two months. DETAILED DESCRIPTION

[0046] In order to further understand the content and features of the present invention, examples of the present invention are given below. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0047] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0048] Example 1

[0049] A method for preparing an anti-icing, self-cleaning and radiative cooling multifunctional coating comprises the following steps:

[0050] Step 1: At room temperature, 1 g of TiO2 nanoparticles, 6 g of α-phosphogypsum, 3 g of NaOH, and 0.5 g of Na2SO4 were added to 30 g of deionized water. The mixture was stirred for 30 minutes and then filtered to obtain a filter cake. The filter cake was microwaved at 100 W for 30 minutes, thoroughly washed (first with deionized water three times, then with anhydrous ethanol three times), and dried at 60°C for 12 hours to obtain a TiO2-α-phosphogypsum mixed powder.

[0051] Step 2: Add 20 mL of anhydrous ethanol, 1.25 mL of deionized water, and 0.53 g of KH570 to a beaker. Stir and heat to 60°C. Then add 6 g of the mixed powder obtained in Step 1. Continue stirring and heating for 2.5 hours, then filter and wash three times with anhydrous ethanol. Dry at 60°C for 12 hours, grind, and sieve through a 90-mesh sieve to obtain modified TiO2 nanoparticles.

[0052] Step 3: Particle size 7-40 nm, specific surface area 100 m 2 0.4 g of superhydrophobic SiO2 nanoparticles (0.4 g / g) and 0.3 g of modified TiO2 nanoparticles obtained in step 2 were added to 15 mL of ethyl acetate dispersion solvent, and magnetically stirred at 700-800 r / min for 15-20 min to obtain a mixed suspension of SiO2 and modified TiO2 nanoparticles;

[0053] Step 4: Add 0.3 g E51 and 0.1 g PEI to the mixed suspension obtained in step 3 and stir magnetically for 2 h to obtain a mixed solution;

[0054] Step 5: Add 0.2 g PDMS and 0.02 g curing agent to the mixture obtained in step 4 and stir magnetically for 1 h to obtain a superhydrophobic coating;

[0055] Step 6: Place the aluminum substrate in a plasma cleaner for 1 minute. Use a 200 μm-high scraper to scrape the aluminum substrate at room temperature. Place the substrate in a 120°C oven and dry it for 2 hours to obtain a multifunctional super-hydrophobic coating of SiO2 and modified TiO2 for anti-icing and radiation cooling.

[0056] Through the above steps, the water contact angle of the coating prepared on the aluminum substrate reached a maximum of 156.5° ( Figure 1 ), the roll angle is 5° ( Figure 2 Compared with the ambient temperature, the temperature difference ΔT on the sample surface of this embodiment can reach up to 20°C, and the average temperature drop is 16.3°C ( Figure 6 、 Figure 7), has excellent cooling effect.

[0057] Example 2

[0058] Compared with Example 1, α-phosphogypsum is not added in step 1, and the rest is the same as Example 1.

[0059] After testing, the water contact angle of the coating prepared on the aluminum substrate reached a maximum of 157.25° ( Figure 1 ), the roll angle is 2.25° ( Figure 2 ). An aluminum substrate and the coating prepared in this example were placed on a cooling table, and 20 μL of deionized water was dripped onto each of them. After the cooling table was started, the freezing process was as follows ( Figure 3 ): Water droplets on bare aluminum begin to freeze at 239 s, and water droplets on the coating are completely frozen after 282 s; water droplets on the sample of this embodiment begin to freeze at 1158 s, and are completely frozen after 1223 s. The freezing delay time is about 4.5 times that of the aluminum substrate, which proves that the coating in this embodiment can significantly prolong the freezing time of water droplets compared with the aluminum substrate and has an excellent anti-icing effect.

[0060] The forces required to detach the deionized water with volumes of 40, 60, 80, and 100 μL after freezing on the sample surface in this embodiment are 5.25, 7.015, 10.411, and 13.992 N, respectively. Figure 4 ), with an average de-icing force of 9.167 N. Compared to the aluminum substrate (average de-icing force of 16.297 N), the sample of this embodiment can reduce the de-icing force by nearly half, proving that the sample of this embodiment is more likely to remove ice from the surface. After 27 cycles of ice formation and ice melting at the same marked position, the water contact angle of the coating of this embodiment remained above 150°, and the water rolling angle was below 10° ( Figure 5 ), which proves that it has good durability in anti-icing scenarios.

[0061] Compared with the ambient temperature, the temperature difference ΔT of the sample surface in this embodiment can reach up to 17.3 ℃, and the average temperature drop is 13.6 ℃ ( Figure 8 、 Figure 9 ), the cooling effect is not as good as that in Example 1, indicating that the cooling effect of the coating is significantly reduced when α-phosphogypsum is not added.

[0062] The sample of this embodiment has passed 26 cycles ( Figure 10 ), after 45 cycles of cyclic abrasion test on 1000 grit sandpaper with a load of 50 g ( Figure 11 ) still maintains super hydrophobic state. The sample is immersed in HCl solution with pH = 2 ( Figure 12 ), pH = 10 NaOH solution ( Figure 13) for 10 days and still maintain super hydrophobic state. The sample was directly exposed to outdoor natural conditions for 2 months. During the whole test process, WCA remained above 150° and SA was less than 10° ( Figure 14 ), the superhydrophobicity of the sample is basically maintained, indicating that the sample is not damaged by rain or other environmental factors and has good weather resistance and long-term stability.

[0063] Example 3

[0064] Compared with Example 1, steps 1 and 2 are omitted, and only 0.5 g of SiO2 nanoparticles are added in step 3. The rest is the same as Example 1. The water contact angle of the tested coating is 156.5° ( Figure 1 ), rolling angle 2.5° ( Figure 2 The coating prepared in this example was placed during the freezing experiment in Example 1, and the freezing process was observed as follows: at 1009 s, the water droplets on the coating began to freeze, and after 1072 s, the water droplets on the coating were completely frozen ( Figure 3 ).

[0065] The forces required to detach the deionized water with volumes of 40, 60, 80, and 100 μL after freezing on the sample surface in this embodiment are 4.979, 8.572, 11.981, and 14.246 N, respectively. Figure 4 ), the average de-icing force is 9.945 N. After 27 ice-melting cycles at the same marked position, the water contact angle of the coating in this embodiment remains above 150° and the water rolling angle is below 10° ( Figure 5 ).

[0066] Compared with the ambient temperature, the surface temperature difference ΔT of the samples in this embodiment can reach up to 16.9 °C, and the average temperature drop is 11.4 °C ( Figure 8 、 Figure 9 ), the cooling effect is not as good as that in Example 1, indicating that the cooling effect of the coating is significantly reduced when modified TiO2 is not added.

[0067] The sample of this embodiment has passed 22 cycles ( Figure 10 ), after 32 cycles of cyclic abrasion test on 1000 grit sandpaper with a load of 50 g ( Figure 11 ) still maintains superhydrophobic state. The sample is immersed in HCl solution with pH = 2 ( Figure 12 ), pH = 10 NaOH solution ( Figure 13 ) for 10 days and still maintain super hydrophobic state. The sample was directly exposed to outdoor natural conditions for 2 months. During the whole test process, WCA remained above 150° and SA was less than 10° ( Figure 14 ).

[0068] Example 4

[0069] Compared with Example 1, α-phosphogypsum is not added in step 1, and the amount of TiO2 nanoparticles added is changed to 0.2 g. The rest is the same as Example 1. The water contact angle of the coating can reach 158.25° ( Figure 1 ), rolling angle 1.25° ( Figure 2 The coating prepared in this example was placed during the freezing experiment in Example 1, and the freezing process was observed as follows: at 1213 s, the water droplets on the coating began to freeze, and after 1292 s, the water droplets on the coating were completely frozen ( Figure 3 ).

[0070] The forces required to detach the deionized water with volumes of 40, 60, 80, and 100 μL after freezing on the sample surface in this embodiment are 3.887, 7.084, 11.314, and 13.056 N, respectively. Figure 4 ), the average de-icing force is 8.835 N. After 27 cycles of ice formation and ice melting at the same marked position, the water contact angle of the coating in this embodiment remains above 150° and the water rolling angle is below 10° ( Figure 5 ).

[0071] Compared with the ambient temperature, the surface temperature difference ΔT of the samples in this embodiment can reach up to 16.5 ℃, and the average temperature drop is 12.3 ℃ ( Figure 8 、 Figure 9 ), indicating that the cooling effect of the coating is significantly reduced when α-phosphogypsum is not added.

[0072] The sample was subjected to 24 cycles of 20 g gravel 40 cm height cyclic impact test ( Figure 10 ), after 41 cycles of cyclic abrasion test on 1000 grit sandpaper with a load of 50 g ( Figure 11 ) still maintains super hydrophobic state. The sample is immersed in HCl solution with pH = 2 ( Figure 12 ), pH = 10 NaOH solution ( Figure 13 ) for 10 days and remained super-hydrophobic. The samples were directly exposed to outdoor natural conditions for 2 months. During the entire test process, WCA remained above 150° and SA was greater than 10° ( Figure 14 ).

[0073] Example 5

[0074] Compared with Example 1, α-phosphogypsum was not added in step 1, the amount of TiO2 nanoparticles was changed to 0.5 g, the amount of SiO2 nanoparticles in step 3 was changed to 0.35 g, and the rest was the same as Example 1. The coating water contact angle was tested to be 155.5° ( Figure 1 ), rolling angle 3.25° ( Figure 2The coating prepared in this example was placed during the freezing experiment in Example 1, and the freezing process was observed as follows: the water droplets on the coating began to freeze at 946 s, and the water droplets on the coating were completely frozen after 1012 s ( Figure 3 ).

[0075] The forces required to detach the deionized water with volumes of 40, 60, 80, and 100 μL after freezing on the sample surface in this embodiment are 6.640, 8.763, 11.232, and 15.175 N, respectively. Figure 4 ), the average de-icing force is 10.453 N. After 27 ice-melting cycles at the same marked position, the water contact angle of the coating in this embodiment remains above 150° and the water rolling angle is below 10° ( Figure 5 ).

[0076] Compared with the ambient temperature, the surface temperature difference ΔT of the samples in this embodiment can reach up to 15.5 ℃, and the average temperature drop is 10 ℃ ( Figure 8 、 Figure 9 ), indicating that the cooling effect of the coating is significantly reduced when α-phosphogypsum is not added.

[0077] The sample of this embodiment has passed 19 cycles in the 20 g gravel 40 cm height cyclic impact test ( Figure 10 ), after 35 cycles of cyclic abrasion test on 1000 grit sandpaper with a load of 50 g ( Figure 11 ) still maintains a superhydrophobic state, and its mechanical properties are poorer than those of the sample in Example 1. The sample is immersed in a pH = 2 HCl solution ( Figure 12 ), pH = 10 NaOH solution ( Figure 13 ) for 10 days with a rolling angle exceeding 10°. The samples were directly exposed to outdoor natural conditions for 2 months. During the entire test process, the WCA remained above 150° and the SA was slightly higher than 10°. Figure 14 ).

[0078] Example 6

[0079] Compared with Example 1, α-phosphogypsum was not added in step 1, 0.3 g of SiO2 nanoparticles and 0.67 g of TiO2 nanoparticles were added in step 3, and the rest was the same as in Example 1. The coating water contact angle was tested to be 154.75° ( Figure 1 ), the roll angle is 4° ( Figure 2 The coating prepared in this example was placed during the freezing experiment in Example 1, and the freezing process was observed as follows: the water droplets on the coating began to freeze at 823 s, and the water droplets on the coating were completely frozen after 882 s ( Figure 3 ).

[0080] The forces required to detach the deionized water with volumes of 40, 60, 80, and 100 μL after freezing on the sample surface in this embodiment are 6.897, 9.592, 13.201, and 15.943 N, respectively. Figure 4 ), the average de-icing force is 11.408 N, which is greater than that of the sample in Example 1. After 27 cycles of ice formation and ice melting at the same marked position, the water rolling angle of the coating in this embodiment is about 15° ( Figure 5 ).

[0081] Compared with the ambient temperature, the surface temperature difference ΔT of the samples in this embodiment can reach up to 14 ℃, and the average temperature drop is 9.6 ℃ ( Figure 8 、 Figure 9 ), the cooling effect is poor compared with the sample in Example 1.

[0082] The sample of this embodiment has undergone 15 cycles ( Figure 10 ), after 25 cycles of cyclic abrasion test on 1000 grit sandpaper with a load of 50 g ( Figure 11 ) maintains a super-hydrophobic state, and its mechanical properties are poorer than those of the sample in Example 1. The sample is immersed in a pH = 2 HCl solution ( Figure 12 ), pH = 10 NaOH solution ( Figure 13 ) for 10 days with a rolling angle exceeding 10°, the sample was directly exposed to outdoor natural conditions for 2 months, and the WCA remained above 150° and the SA was greater than 10° ( Figure 14 ), the super-hydrophobicity of the sample in this embodiment is lost, and the acid and alkali resistance and weather resistance are poorer than those of the sample in Example 1.

[0083] Example 7

[0084] Compared with Example 1, steps 1 and 2 were omitted, and only 0.5 g of TiO2 nanoparticles was added in step 3. The rest was the same as in Example 1. The water contact angle of the coating was tested to be 139.25° and the sliding angle was 43°, indicating that excessive use of nano-TiO2 would cause the coating to lose its superhydrophobicity.

[0085] Example 8

[0086] Compared to Example 1, the amount of NaOH added in Step 1 was 4g, and the rest of the results were the same as in Example 1. In the hydrophobicity test, the coating had a water contact angle of 157.3° and a rolling angle of 2.8°. In the cooling performance test, the temperature difference ΔT between the sample surface and the ambient temperature reached up to 19.5°C, with an average temperature reduction of 16.0°C, demonstrating excellent cooling performance.

[0087] Example 9

[0088] Compared to Example 1, the amount of Na2SO4 added in Step 1 was 0.4g, and the remaining results were the same as in Example 1. In the hydrophobicity test, the coating had a water contact angle of 155.3° and a rolling angle of 4.5°. In the cooling performance test, the temperature difference ΔT between the sample surface and the ambient temperature reached up to 19.5°C, with an average temperature reduction of 16.4°C, demonstrating excellent cooling performance.

[0089] Example 10

[0090] Compared to Example 1, the amount of α-phosphogypsum added in Step 1 was 5g, and all other properties were the same as in Example 1. In the hydrophobicity test, the coating had a water contact angle of 156.8° and a rolling angle of 3.7°. In the cooling performance test, the temperature difference ΔT between the sample surface and the ambient temperature reached up to 19.6°C, with an average temperature reduction of 16.1°C, demonstrating excellent cooling performance.

Claims

1. A method for preparing an anti-icing, self-cleaning, and radiative cooling multifunctional coating, characterized in that: The following steps are involved: Step 1: Add α-phosphogypsum, NaOH and Na2SO4 to deionized water, stir, add TiO2 nanoparticles, continue stirring, filter, microwave, wash and dry to obtain α-phosphogypsum-TiO2 mixed powder; Step 2: Anhydrous ethanol, deionized water, and KH570 are mixed and stirred, and after heating, the mixed powder obtained in step 1 is added, and the mixture is further stirred under heating conditions, and then filtered, washed, dried, ground, and sieved to obtain modified TiO2 nanoparticles; Step 3: adding super-hydrophobic SiO2 nanoparticles and modified TiO2 nanoparticles to an ethyl acetate dispersion solvent, and ultrasonically dispersing the super-hydrophobic SiO2 nanoparticles to obtain a mixed suspension of the super-hydrophobic SiO2 nanoparticles and the modified TiO2 nanoparticles, wherein the mass ratio of the super-hydrophobic SiO2 nanoparticles to the modified TiO2 nanoparticles is (1:0.1) to (3:2). Step 4: Add E51 and PEI to the mixed suspension obtained in step 3 and stir to obtain a mixed solution; Step 5: Add PDMS and its curing agent to the mixed solution obtained in step 4 and stir to obtain a super hydrophobic coating; Step 6: The coating obtained in step 5 is scraped onto the substrate using a scraper method, and after the solvent is dried, an anti-icing, self-cleaning, and radiant cooling multifunctional coating is obtained.

2. The method for preparing the anti-icing, self-cleaning, and radiant cooling multifunctional coating according to claim 1, characterized in that: In the step 1, the mass ratio of TiO2 nanoparticles: α-phosphogypsum: NaOH: Na2SO4 is 0.3-3: 3-9: 1-5: 0.2-2; the magnetic stirring speed is 800-900 r / min; The microwave power was 60 W ~150 W, and the microwave irradiation time was 2 ~ 8 min.

3. The method for preparing the anti-icing, self-cleaning, and radiant cooling multifunctional coating according to claim 2, characterized in that: In the step 1, the mass ratio of TiO2 nanoparticles: α-phosphogypsum: NaOH: Na2SO4 is 1:6:3:0.5; the magnetic stirring speed is 800 r / min; The microwave power was 100 W, and the microwave irradiation time was 3-5 min.

4. The method for preparing the anti-icing, self-cleaning, and radiant cooling multifunctional coating according to claim 1, characterized in that: In step 2, the mass concentration of KH570 is 0.025-0.1 g / mL; and the stirring temperature is 50°C-80°C.

5. The method for preparing the anti-icing, self-cleaning, and radiant cooling multifunctional coating according to claim 1, characterized in that: In step 3, the particle size of the super-hydrophobic SiO2 nanoparticles is 7-40 nm, and the specific surface area is 100-200 m 2 / g; the particle size of the modified TiO2 nanoparticles is 90-120 mesh, and the total mass concentration of the suspension of superhydrophobic SiO2 nanoparticles and modified TiO2 nanoparticles is 0.053-0.1 g / mL.

6. The method for preparing the anti-icing, self-cleaning, and radiative cooling multifunctional coating according to claim 1, wherein: In step 4, the mass ratio of E51:PEI is 3-5:1, and the stirring temperature is 65-75°C.

7. The method for preparing the anti-icing, self-cleaning, and radiative cooling multifunctional coating according to claim 1, wherein: The mass concentration of PDMS in step 5 is 0.013-0.1 g / mL, and after stirring for 30 min-1 h, the mixture is cured at 120-140 °C for 2-3 h.

8. The method for preparing the anti-icing, self-cleaning, and radiative cooling multifunctional coating according to claim 1, wherein: In step 6, the coating comprises, by weight, 30 to 50 parts of superhydrophobic SiO2 nanoparticles, 5 to 50 parts of modified TiO2 nanoparticles, 20-30 parts of E51, 10-15 parts of PEI, and 15-20 parts of PDMS, with the mass ratio of PDMS to curing agent being 10-20:

1.

9. The method for preparing an anti-icing, self-cleaning, and radiative cooling multifunctional coating according to claim 1, characterized in that: In step 6, the scraping film thickness of the scraping method is 100-300 μm, and the material of the substrate includes any one of a glass sheet, an aluminum sheet, a copper sheet, and a carbon steel sheet.

10. Application of the coating obtained by the preparation method of the multifunctional coating according to any one of claims 1 to 9 in materials having any one or more properties of anti-icing, radiant cooling, and self-cleaning.

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